Third Heart Sound Gallop

A third heart sound occurs early in diastole. In young people and athletes it is a normal phenomenon. In older individuals it indicates the presence of congestive heart failure. The third heart sound is caused by a sudden deceleration of blood flow into the left ventricle from the left atrium. In the anatomy video you will see a thin-walled, dilated left ventricle with generalized decreased vigor of contraction. In the presence of a third heart sound (S3) the first heart sound is decreased in intensity while the second heart sound is increased in intensity. The third heart sound is a low frequency sound best heard with the bell of the stethoscope pressed lightly on the skin of the chest.

Auscultation Sounds

Patient Recording

Patient Recording - Half Speed Playback

Position

The patient's position should be supine.

Listening Tips

S1:Reduced intensity
S2:Increased intensity
Diastole:S3 early in diastole, low-pitched, heard during expiration

Waveform (Phonocardiogram)

Observe

//embedding heart animation

Authors

These authors contributed the audio recordings and text found in this reference guide: Jon Keroes, MD,Diane Wrigley, PA, and David Lieberman.
Medically reviewed by Dr. Barbara Erickson, PhD, RN, CCRN.

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